Metal coating apparatus



July 17, 1962 Filed July 30 1957 E. P. SCHREYER ET AL 3,044,439

METAL COATING APPARATUS 8 Sheets-Sheet l INVENiORS.

ly 7, 1962 E. P. SCHREYER ETAL 3,044,

METAL COATING APPARATUS Filed Jul 30. 1957 s Sheets-Sheet 2 July 17, 1962 E. P. SCHREYER ETAL 3,044,439

METAL COATING APPARATUS 8 Sheets-Sheet 4 Filed July 30 195'? INVENTOR. 5011 44 0 P. sc/net'rae y/mes/uu a. W/l/TF/AZO B July 17, 1962 E. P. SCHREYER ETAL 3,044,439

METAL COATING APPARATUS Filed July so, 1957 8 Sheets-Sheet 5 F/ 6. 6 INVENTORS.

July 17, 1962 Filed July 30, 1957 8 Sheets-Sheet 6 INVENTORS sou 42o P. sow: yzz #4251941! 4 lV/Y/IF/EZD f/f m July 17, 1962 E. P. SCHREYER ET AL 3,044,439

METAL COATING APPARATUS Filed July 30. 1957 8 Sheets-Sheet 7 INVENTOR.

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METAL COATING APPARATUS.

Filed July 30, 1957 8 Sheets-Sheet 8 INVENTOR. Eye n20 2 saw: yze ynmeslwzz 4. Wfl/TF/A'LD 4444, @MIM United States Patent 3,044,439 METAL COATDJG APPARATUS Edward P. Schreyer, Ridgefield, Conn., and Marshall G. Whitfield, Garden City, N.Y., assignors to Whitfield Laboratories, Inc, Ridgefield, Conn., a corporation of Connecticut Filed July 30, 1957, Ser. No. 675,085 19 Claims. (Cl. 118107) This invention relates to the art of metal coating and more particularly to a method and equipment for metal coating a valve.

As conducive to an understanding of the invention it is noted that where valves are used, for example, in an internal combustion engine, they are subject to attack by products resulting from the combustion of fuels, particularly those containing lead compounds. As a result, the portion of the valve head exposed in the combustion chamber is subject to rapid oxidation and high temperature corrosion due to the hot combustion gases. This causes valve failure due to the corrosion of the valve seating face or the portion of the valve stem immediately adjacent the valve head.

It is known that aluminum and its alloys have the ability to form coatings having exceptional heat resistant, oxidation resistant, corrosion resistant and erosion resistant properties when alloyed with base metals such as iron,

titanium and the like having a high enough melting point to permit the application of such aluminum and its alloys.

Where to overcome the difficulties above pointed out aifecting the valve, the latter is coated with a metal, such as aluminum or its alloys which, by difiusion, alloys with a base metal, control of the thickness of the resulting alloy formed on the valve is essential. Such control of the thickness of the surface alloy layer is important because differences in the coefiicients of expansion of the alloy layer and the base metal can set up stresses which result in scaling or spalling. Also, since the alloy layers are of a hard brittle nature, thicker layers are more prone to develop cracks than are thinner layers. Spalling or cracks may be caused by vibration, impact or thermal shock and result in corrosion of the underlying base metal and failure of the article.

Furthermore, where the excess aluminum remaining over the alloy coating formed, is relatively thick, since the aluminum has a lower melting point than the alloy, when subjected to the heat of the combustion gases in use of the valve, such excess aluminum will tend to diffuse further into the base metal so that the alloy coating becomes thicker with the disadvantages above pointed out. In addition, if such excess unalloyed aluminum is not of uniform thickness, subsequent alloying thereof in use of the article or if the article is subjected to stabilizing heat treatment prior to use, will cause undesirable inequality in thickness of the alloy coating.

Where, to control the thickness of the aluminum, drainage in molten salt is attempted, the drainage is generally insufficient and cannot be dependably controlled. Consequently the resultant article may have excessively thick or non-uniform alloy and/ or aluminum coatings which do not provide the desired protective characteristics.

In addition, the drainage operation is relatively difiicult to perform and increases the time required for the coating cycle with resultant decrease in the rate of production.

It is accordingly among the objects of the invention to provide a relatively simple method and correspondingly simple equipment for providing metal objects such as valves and other components exposed to elevated temperatures and corrosion, with a corrosion resistant, heat resistant and erosion resistant protective alloy coating of aluminum or the like of predetermined thickness, which coat- 3,044,439 Patented July 17, 1952 ing will be substantially identical for all items coated in a run, and which objects are coated relatively rapidly and are substantially devoid of excess and/or non-uniform coating material which might diffuse into the base metal to increase the thickness of the alloy coating to an undesired amount.

According to the invention from .its broadest aspect, the article has a coating of aluminum or aluminum alloy applied thereto and covering substantially the entire effective surface thereof. With a coating at a temperature sufliciently high so that it will diffuse into the base material, an alloy will be formed therewith to provide the desired protective coating. When the protective coating is of sufficient desired thickness, excess molten aluminum on the surface of the article is removed by brushing with rapidly moving wire brushes which, in addition to removing the excess molten aluminum, also spread the latter 4 over the article to ensure that the entire surface thereof is uniformly coated.

According to one embodiment of the invention, the articles are dipped into a bath of molten aluminum or the like and after the articles have been in the bath a predetermiued time, dependingupon the thickness of the protective alloy coating desired, it is removed from the bath and While the surface aluminum is still molten, excess aluminum is removed by the application to the articles of rapidly moving wire brushes which also ensure uniform coating thereof.

According to another embodiment of the invention, the article is coated by means of metallizing, using spray guns, and thereafter the sprayed article I is heated as by induction heating or gas heating for a suflicient period to permit the formation of a protective alloy coating of desired thickness and thereupon while the surface aluminum is still molten, any excess aluminum is removed by the application to the article of rapidly moving wire brushes, which also insures uniform coating thereof.

According to one feature of the invention, where the aluminum coating is applied by dipping the article into a molten bath, the article is vibrated to enhance bonding of the aluminum to the article and to reduce the time required for the article to be coated.

In the accompanying drawings in which-are shown one or more of various possible embodiments of the several features of the invention,

FIG. 1 is a front elevational view of the machine,

'FIG. 2 is a rear elevational View thereof,

FIG. 3 is a side elevational view taken along line 33 of FIG. 1,

FIG. 3A is a detail sectional view taken along line 3A--3A of FIG. 3,

FIG. 4 is a fragmentary side elevational view taken along line 44 of FIG. 1,

FIG. 5 is a plan view with parts broken away of the article holding members and supporting plate,

FIG. 6 is a detail view taken along line 66 of FIG. 2 showing the article holder actuating mechanism,

FIG. 7 is a transverse sectional view taken along line 7-7 of FIG. 2,

FIG. 8 is a view similar to FIG. 7 taken along line 8-8 of FIG. 2,

FIG. 9 is a top plan view of the motor mount and brush driving mechanism,

FIG. 10 is a sectional view taken along line 10-10 of FIG- 2,

the equipment comprises a substantially rectangular base 11 having a substantially rectangular opening 12.

Rising from each of the sidesof the base 11 is an upright standard 13, preferably a channel member, a cross piece 14 83 the upper ends of the standards 13 retaining the latter in parallel relationship.

Extending through transversely aligned openings 15 in each of the standards 13 adjacent their lower ends, is a shaft 16 which rotatably mounts thereon-a drum assembly 17. Each end 18 of the shaft 16 is rectangular as shown in FIG. 3 and is positioned in an elongated slot 19 in an adjustment block'21 affixed to the associated standard as by screws 22. Each of the blocks 21 has a pair of vertically aligned bores 23 in each of which is positioned a screw 24, the head of which has a socket to receive an Allen wrench for example, to rotate the associated screw. The inner ends of the screw are adapted to abut against the rectangular ends 18 or the shaft 16 so that thevertical position thereof may be adjusted.

The drum 17, FIGS. 1 and 2, comprises a pair of side plates 27, 28 illustratively octagonal as shown in FIG. 3, having transversely aligned openings29 through which the shaft 18 extends. The plates 27, 28 are retained in spaced relationship by means of a plurality of tie rods 31, the threaded ends of which extend through the plates and are secured as by nuts 32'.

The drum 17 is restrained from axial movement on shaft 16 by means of collars 33 on each side of plates 27, 28 afiixed to shaft 16 as by set screws 34.

Extending between the side plates 27, 28 are spindle plates 35. Four spindle plates are illustratively provided, each substantially rectangular and designated 35A, 35B, 35C and 35D. The spindle plates extend between pairs of the longitudinally opposed edges 36 of the plates 27, 28, being equidistantly spaced and mounted so that they may move slightly in direction parallel to the axis of shaft 16. I V v To permit such movement, each of the plates 35 has a pair of spaced recesses 37 (FIG. 2) in each of which one end of a pin 38 is positioned and secured to the plates 35 as by set pin 39. The pins Bis-extend through aligned openings 41in plates 27, 28 and a spring 42 at each end 'of the plate seatedin aligned recesses 43 in plates 35 and plates 27, 28 centers the plates 35 between plates 27 ,'28 yet affords movement thereof to permit the associated vibrator 45, later described, freedom to vibrate the associated plate 35, yet isolate the vibrations to this plate from the other plates 35. r

As shown in FIG. 1, the vibrator 45 which is preferably of the air operated type has its housing 46 secured by screws 47 to blocks 48 affixed to the associated plate 35 on the inner side thereof.

Each of the vibrators 45 is connected by an air line 51 which extends through an associated opening in plate 28 to a fitting 52 (FIGS. 1, 2 and extending into one of the side walls 53 of a rectangular valve block or manifold 54, the latter having a central opening 55 through which the shaft 16 extends, the block 54 being secured to the outer surface of plate 2821s by screws 56.

As shown in FIGS. 2 and 10, the valve block 54 has a central portion 58 and two side portions 59 which straddle the central portion and which retain the packing 61 in position. The end of shaft 16 adjacent plate 28 has an axial bore 62 threaded at its outer end as at 63 to receive an air line 65 (FIG. 1). Leadinginto the inner end of bore-62 is a transverse arcuate recess 66 of greater width at its outer end and the central portion 58 of block 54 has four radial bores 67 to each of which adding 52 is connected.

Thus, only one of the fittings 52 will be connected to the recess 66 at a time and in the illustrative embodiment,

the fitting 52 associated with the plate 35 when at posi- 1 gears 75 driving the spindles 72 will be rotated in the '71, four spindles being illustratively shown. As all of the plates 35 and the associated spindles 71 are identical, only one of the spindles on plate 35D (FIG. 5) will be described in detail.

As shown. in FIG. 5, each spindle comprises an outer sleeve 72 which extends through a bushing 73 press fitted in a suitable opening 74 in plate 35]). Encompassing the portion of sleeve 72 extending above plate 35D is a gear 75 which is secured to the sleeve 72 by a key 76. To restrain vertical movement of the sleeve 72 in bushing 73, a snap ring 77 is positioned in an'annular groove 78 in the sleeve on each of the opposed sides of gear 75, and a thrust washer 79 encompasses the sleeve 72 and is positioned against the undersurface of bushing 73.

Slidably mounted in each of the sleeves 72 is a draw bar 81 which has a head 82 at its outer end against which one end of a coil spring 83 abuts, the other end of the spring abutting against the end 84 of the sleeve normally to urge the draw bar outwardly.

The inner end 85 of the draw bar is internally threaded to receive the correspondingly threaded encl86 of a draw collet 87 of conventional type such as that put out by South Bend Lathe Works of South Bend, Indiana.

The collet 87 is longitudinally split as at 88 in conventional manner and the outer end thereof is beveled as at 91 to react against the correspondingly beveled inner surface of sleeve 72 so that when the draw bar 81 is moved outwardly by the action of spring 83, the collet will close to grip in conventionalmanner.

As previously described, four spindles 71 are mounted on each plate 35. To rotate the spindles simultaneously in the same direction three idler gears 94, 95 and 96 are provided rotatably mounted on stud shafts 97 afiixed to the plates 35, the gears 94 and 96 meshing with the two gears 75 on the left and right hand sides of the plate (FIG. 1) and the gear 95 meshing with the two central gears 75. Thus, upon rotation of the gear 95 in one direction, the

opposite direction.

Means are provided to move the draw bars 8 1 inwardly against the tension of spring 83 to open the draw collet 87. This operation which occurs at position A (FIG. 3) is accomplished in the illustrative embodiment shown by means of a plurality of cams 101 (FIGS. 2 and 6) pinned as at 102 to shaft 16, and aligned respectively with the spindles 71. Each of the cams has a protruding portion 103 which will be aligned with the spindles 71 when they are at position A.

Associated with each of the spindles is a rocker arm 104 pivotally mounted at one end on a rocker arm rod 105 extending between the plates 27, 28. The free end of each rocker arm has a projecting finger 106 which is positioned between the head 82 of each draw bar 81 -and the surface 107 of the associated cam 101 as shown in FIG. 6.

Thus, upon rotation of the drum in a counterclockwise direction to the position shown in FIG. 6 when the finger 106 of the rocker arm 104 rides over thecam surface 107, the rocker arm 104 will be moved outwardly or in a counterclockwise direction about its pivot 105 to force the draw rod 81 inwardly against the tension of spring 83. Thus, when the drum has rotated to position A (FIG. 6) for example, the projection 103 will have moved the draw rod to its maximum outward position for full opening of the draw collet 87. a

Means are provided to rotate the drum 17 in steps of 90 degrees so that the plates 35 may be indexed from position to position. A 7

To this end, as illustratively shown in FIGS. 1, 2 and 3, a jack 112, illustratively air operated, is pivotally mounted at one end as at 113 to the standard 13 at the right side of the machine, referring to FIG. 1, so as to pivot on an axis parallel to that of shaft 16. The plunger rod 114 of the jack 112 adjustably mounts at its lower end a pawl 115, which has a drive finger 116 at its lower end. The edge of the pawl between the finger 116 and the upper end 117 thereof is cut out as at 118 to provide clearance for the drum drive pins 119.

As shown in FIG. 3, four of such pins are provided extending laterally outward from- -the plate 27 adjacent its periphery. The pins are so located that when initially engaged by the pawl finger 116, and the latter is moved downwardly by the actuation of jack 114, the drum will be rotated 90 degrees.

Means are provided to move the pawl finger 116 into engagement with the successive drive pins 119 upon upward movement of the pawl to drive position.

To this end, a coil spring 121 is provided connected at one end to standard 13 and at its other end to jack 112 as at 122. Thus, when the pawl is raised, the spring 121 will retain the cut away portion 118 of the pawl against the upper pin 119 (FIG. 3) and when the lower end of the cut out portion has passed the upper pin 119, the spring 121 will move the jack and pawl inwardly about pivot 113 so that finger 116 will be in alignment with the upper pin 119 to react thereagainst upon energization of the jack 112.

Means are provided to guide the pawl 115 upon movement thereof by jack 112. To this end, as shown in FIGS. 1, 3 and 3A, a pair of L-shaped bars 125 secured together as by bolts 126 are atfixed as by bolts 127 to the upper end of jack 112. The legs 128 of the bars 126 are slightly spaced and as shown in FIGS. 3, 3A, a pin 129 afiixed to pawl 115 extends into such space to guide the pawl as it is reciprocated.

Means are provided to lock the drum after each rotation thereof through an angle of 90 degrees to insure that it is properly indexed. To this end, as shown in FIGS. 1 and 3, a bell crank 131 is pivotally mounted as at 132 on a block 133 aflixed to standard 13 on the right side of the machine as shown in FIG. 1. Interposed between the bell crank 131 and the block 133 and secured to the latter is a spacer block 134 which vertically aligns the bell crank with the end 135 of the pawl. The spacer block has a stop conformation 136 against which the horizontal leg 137 of the bell crank is normally seated under the urging of a coil spring 138 connected at one end as at 139 to leg 137 and at its other end to the base of the machine.

Thus, when the pawl 115 has been moved to its lowermost position as shown in FIG. 3, the end 135 thereof will seat against the leg 137 which is the limit of the downward stroke of the jack. Consequently, the lower pin 119 (FIG. 3) will be retained between the finger 116 of the pawl and the beveled surface 141 of the leg 142 of the bell crank properly to index the drum.

In the event the drum 17 should have moved faster than the pawl so that the lower pin 119 struck the beveled surface 141 before the end 135 of the pawl abuts against finger 137, the bell crank would have been pivoted in a clockwise direction from the position shown in FIG. 3 against the tension of spring 138. Consequently, the drum would not be properly indexed. However, when the pawl 115 completed its downward stroke and the end 135 thereof abutted against finger 137 it would rotate the bell crank in a counterclockwise direction until leg 137 was seated against stop 136. This will rotate the drum backward to its proper 90 :degree position and thereupon it would be locked in such position in the manner previously described.

To ensure that the drum will be dependably locked in each indexed position, an auxiliary locking mechanism is provided.

This mechanism as illustratively shown in F168. 1 and 2, comprises a jack 151, also air operated, which is mounted on the standard 13 at the left side of the machine as.shown in FIG. 1. The plunger rod 152 of the jack 151 which is vertically mounted, rides through aligned openings in guide blocks 153. The lower end 154 of the plunger is designed to enter a notch 155 in a locking block 156, four of which are provided, afiixed to the outer surface of plate 28-aligned with each of the spindle plates 35 thereof. The notch 155 is so positioned that with each degree rotation of the drum, as previ ously described, the notch will be directed upwardly in alignment with the plunger 152 which will be moved into the notch upon actuation of the jack 151.

Means are provided to remove excess coating material from the objects being processed. Such means in the illustrative embodiment shown are located to act upon the objects at position C, referring to FIG. 3.

To this end, as shown in FIGS. 2, 3, 7 and 8, a pair of plates 161 are affixed respectively to each of the standhas a vertical shaft 167 on which a worm 168 is mounted.

The worm meshes with a worm gear 169 afiixed on a shaft 171 rotatably mounted on plate and centrally located thereon. The shaft 171 also mounts a drive gear 172 with which the drive gear 95 on each of the plates 35 is adapted to be vertically aligned so that it may be driven by gear 172.

The motor shaft 167 also mounts a gear 175 which meshes with an idler gear 176, FIG. 9, that engages a gear 177 of a right angle drive 178 to rotate the shaft 179 of the latter. The shaft extends through an opening in a brush plate 181 which extends between a pair of arms 182 pivotally mounted as at 183 to a pair of parallel arms 184 extending from motor plate 165. The portion of shaft 179 between the right angle drive 178 and the plate 181 is flexible to permit pivotal movement of arms 182 to adjust the position of said plate 181.

Mounted on the protruding end 185 of shaft 179 is a pair of wire brushes 186, adapted to rub against the article being processed. The shaft 179 mounts a gear 187 which meshes with an idler gear 188 that engages a gear 189 affixed to a shaft 191 which also extends through brush plate 181- and mounts a pair of wire brushes 186 thereon.

The brushes 186 and 186' are designed to be held against the pairs of articles on the left and right sides of the plates 35 to eifect rubbing action th'ereagainst. Means are provided to reciprocate the plate 165 to move the drive gear 172 thereof against gear 95 and to move the brushes 136 and 186' against the mticles. In the illustrative embodiment shown, such means comprise a jack 192, also air operated, which is mounted at its upper end to the cross bar 14 of the frame and depends therefrom.

The jack has a plunger rod 193 which is secured as by set screw 194 in a block 195 aifixed to the plate 165 as shown in FIG. 2.

In order to reduce the size of the jack 192 required to reciprocate the plate 165 and the mechanism thereon, a counterweight 201. is provided extending transversely across the front of the equipment as shown in FIG. 1. The counterweight 201 is suspended by cables 202 which ride around pulleys 203 depending from cross member 14, the cables being secured to brackets 2114 mounted on plate 165 as shown in FIG. 3.

Means are provided to operate the various jacks in timed relation so that the drum 17 will be rotated step by step and locked at each position and also to perform the va riousother steps in the coating operation. Asany suitable means such as a disc timer T reacting against a plurality of air switches S may be employed for this purpose, it will not be described,

'thereagainst.

7 Operation The equipment in the illustrative embodiment shown is positioned over a pot P of coating material such as a bath of molten aluminum with the rectangular opening 12 in the base 11 aligned with the open mouth M of the ner so that the heads of the valves are substantially aligned and the timer T is actuated.

As the drum 17 at, this time is locked by the jack 151 (FIG. 1), the latter is first actuated to move its rod 152 out of notch 155 in the associated block 156. Thereupon the jack 112 which has had its plunger rod 114 previously raised, is actuated to move its plunger rod 114 downwardly. As a result, the finger 116 of pawl 115 will engage the topmost pin 119, FIG. 3, to exert force As the end 135' of pawl 115 is no longer engaging the leg 137 of hell crank 131, the lower pin 119 (FIG. 3) and hence the drum 17 will no longer be locked and as the drum rotates, the lower pin 119 will engage the leg 142 of the released bell crank 131 to pivot the latter. As the drum 17 rotates in the direction of the arrow (FIG. 6) the rocker arms 1% will move away from the projections 103 of the cams and the springs 83 of the spindles 71. will move the draw bars 81 and the collets 87 inwardly to lock the valve stems in position. a

With further rotation of the drum, when it has moved substantially 90 degrees, the end 135 of the pawl 115 (FIG. 3) will abut against leg 137 of the bell crank 138 to lock the pin 119 in position, the drum having now rotated 90 degrees with the valves V in vertical position extending below the base plate as shown in FIG. 3 and immersed in the pot P of molten aluminum.

Thereupon, the jack 151 is actuated to move its plunger 152 into the associated notch 155 in block 156 to lock the drum in position. The jack 112 is then actuated in opposite direction to retract its plunger 114 and to move the pawl 115 upwardly so that finger 1'16 thereof will be positioned by spring 121 directly over the next pin 119 ready for the next cycle of operation.

At this time, referring to FIGJlO, the block 54 will have been rotated so that the bore 67 associated with the spindles carrying the valves V now immersed in the pot P will be aligned with the arcuate recess 66 so that the associated vibrator 45 will be energized to cause vibration of the associated plate 358. As this plate is'slidably mounted on pins 38, it will vibrate readily and by reason of the slidable mount of the other plates 35, little vibration will be imparted thereto.

By reason of the vibration imparted to the valves V in the pot P of aluminum, the aluminum will adhere to the entire surface of the valve in the pot, so that the valve does not have to remain in the bath for an excessive period to accomplish such complete coating which, due to the high temperature of the bath might tend to. dissolve the base metal of the valve.

While the valves are in the molten bath, the aluminum will start to alloy with the base metal of the valve to a form the desired protective coating. After a predetermined period of time, depending upon the time it is desired to retain the valves in the molten bath, to secure the desired thickness of the alloy coating which is determined empirically, the timer T again actuates the jack 112 to rotate the drum 17 through a second angle of 9'0 degrees and during the course of the 90 degree movement, thevalves V are moved out of the molten bath to position C. The drum '17 is locked in position as pre- -viou sly described'and the timer T then actuates the jack 1-91 to lower the mounting plate 165 and also energizes the motor 166 to rotate its shaft 167. Rotation of shaft 167 will'cause rotation of drive gear 172 as well as the brushes 186, 186. When the plate 16Shas been lowered sufiiciently, the gear 172 will engagegear to rotate the spindles 71 and the valves V held thereby. At this time the brushes 186, 186' will also engage the valves and excess molten aluminum thereon will be wiped off.

After a predetermined period'of time, the jack 191 is actuated to lift plate 165 to cause the gears 172 and 95 to disengage to stop further rotation of the spindles. The motor 166 is now de-energized and the locking jack 151 is actuated to unlock the drum. The jack 112 is then actuated to again rotate the drum to advance a new set of uncoated valves from position A to position B to be immersed in the pot of aluminum, and to advance the valves in the pot of aluminum to position C for brushing as previously described.

When the coated valves are moved from position C to position D and then to position A, the collets 87 will be opened as previously described so that such coated valves may be removed and replaced by fresh valves to be coated.

The embodiments shown in FIGS. 11 and 12 are similar in many respects to the embodiment shown in FIGS. 1 to 10 except that the coating is applied by spraying and an independent source of heat is employed to raise the coating on the valves to molten condition.

Referring to FIG. 11 in which parts corresponding to those in FIGS. 1 to 10 have the same reference numerals primed, the drum 17' is indexed in steps of 90 degrees from position A to positions B, C and D by means of a pawl which in this case reacts against the drive pins 119 by upward motion eifected by the jack 112'.

The valves V are loaded at position A in the manner described with respect to the embodiment of FIGS. 1 to 10. After a predetermined period, under control of a timer (not shown), the drum 17' is rotated in a clockwise direction by pawl 115 tomove the valves V to position B, where the spray heads 207 which are positioned in juxtaposition on the valves V will deposit a coating of aluminum on the surface thereof. After a predetermined period of time, the timer will cause the drum 17' to again be rotated 90 degrees to advance the coated valves V to station C. At this station the Valves will be aligned with an induction heater 208 which will cause the temperature of the valves V and the aluminum sprayed coating thereon to be raised so that the coatings will become molten. After a predetermined period of time, suificient to permit an alloy coating of desired thickness to be formed on the valves V, the drum 17' is again rotated through an angle of 90 degrees to position D.

Thereupon, the jack 209 is actuated causing the carriage 211 to move to the left. This carriage carries brushes 212 which are driven through an associated gear train 213, by a motor 214. The rotating brushes when they engage the valves will rub off excess aluminum thereon as desired. 7

Afterfla predetermined period of time, the carriage 211 is retracted and the drum 17 again rotated 90 degrees to move the finished valves back to position A at which position the valves are released in the manner previously described.

The embodiment shown in 'FIG. 12 is similar to the embodiment shown in FIG. 11 and corresponding parts have the same reference numerals.

In the embodiment of FIG. 12, the sprayed valves V' are heated to a temperature suflicient to render the sprayed coatings molten and are also brushed at the same position D. Thus, gas jets 215 react against the valves V to heat the latter and after the coatings thereon have become molten and suflicient time has elapsed to permit the formation of an alloy Coating of desired thickness, the brushes 212' are moved into engagement with the valves to remove excess aluminum thereon.

With the method and equipment above described, the article may have an alloy coating or layer formed at the surface thereof of desired thickness. The thickness of the alloy layer is a factor of the temperature of the molten coating material determined either by the pot tempera ture, the induction heating temperature or the gas jet temperature; the time that the coating material is molten, which determines the amount that will diffuse into the base metal, and the efiiciency of removal of excess material so as to prevent further diffusion in use. Since all of such variables may readily be controlled, it is apparent that once an article has had a protective layer formed thereon, by using the same factors for identical articles, they will all have substantially the same protective layer formed thereon and mass production is then relatively simple.

The article thus protected by the method and equipment herein described is not readily subject to oxidation, corrosion or erosion and hence has long life.

Although the method and equipment above disclosed has been illustratively described with respect to its application to coat valves, it is of course to be understood that it is Within the scope of the invention to use such method and equipment to coat other articles such as turbine blades, valve guides and the like.

As many changes could be made in the above method and equipment, and many apparently widely different embodiments of this invention could be made without departing from the scope of the claims, it is intended that all matter contained in the above description or shown in the accompanying drawings shall be interpreted as illustrative and not in a limiting sense.

Having thus described our invention, what we claim as new and desire to secure by Letters Patent of the United States is:

1. Equipment for coating articles comprising a plurality of holders for such articles, a movable support for said holders, the latter being mounted on said support to hold the articles in spaced relation to move in unison with the movement of said support, an article coating station having means to effect coating of the article when at such station, an article brushing station comprising a brush, means to rotate said brush and a movable mount for said brush, means to effect step by step movement of said support to advance the articles in the holders thereon from said coating station to said brushing station, means to effect movement of said brush mount to move the brush thereon into engagement with the article when the latter is at the brushing station and means to retain said brush in engagement with the article for a predetermined period of time.

2. The combination set forth in claim 1 in which said support is rotatable about an axis, and the means to effeet movement of said support in steps rotates the support about its axis.

3. The combination set forth in claim 1 in which said coating means comprises a receptacle for molten coating material, and said support when advanced to said coating station immerses such article in said molten coating material.

4. The combination set forth in claim 3 in which means are provided to vibrate such article when at said coating station.

5. The combination set forth in claim 1 in Which the coating means comprises spray means, a movable mount for said spray means, and means to effect movement of said mount toward said coating station when the article is at such station to spray a coating thereon.

6. The combination set forth in claim 5 in which means are provided to heat said article after it has been advanced past said coating station.

7. The combination set forth in claim 5 in which means are provided to heat said article after it has been advanced past said coating station, said means comprising an induction heater.

8. The combination set forth in claim 1 in which the coating means comprises spray means, a movable mount for said spray means, means to effect movement of said mount toward said coating station when the article is at such station to spray a coating thereon, gas heating means at said brushing station and means to actuate said heating means when such article is at the brushing station and to deactuate said heating means prior to movement of the brush into engagement with the article.

9. The combination set forth in claim 1 in which said movable support comprises a shaft, a drum assembly mounted on said shaft and rotatable about the axis thereof, a plurality of article holders are mounted on said drum assembly and spaced therearound, saidholdersex tending outward from said drum assembly and means to effect rotation of said drum assembly in predetermined steps to advance the article in the holders from station to station.

10. The combination set forth in claim 9 in which means are provided releasably to lock said drum assembly after each step by step rotation.

11. The combination set forth in claim 9 in which the means to rotate said drum assembly comprises a plurality of projections extending from one end of the drum and equidistantly spaced therearound and a reciprocable member adapted to engage one of said projections to rotate said drum through an angle determined by the stroke of said reciprocable member in one direction.

12. The combination set forth in claim 9 in which the means to rotate said drum assembly comprises a plurality of projections extending from one end of the drum and equidistantly spaced therearound, an actuating member having a casing pivotally mounted at one end on an axis parallel to the axis of the drum and a reciprocable plungen'a pawl mounted at the outer end of said plunger, said pawl having a drive finger at its free end adapted to engage one of said projections, whereby when said plunger is moved toward the drum and the drive finger engages one of the projections, the drum will be rotated through an angle determined by the stroke of said plunger toward said drum.

13. The combination set forth in claim 12 in which means are provided to index said drum, said means comprising a pivoted substantially L-shaped bell crank having a pair of legs and stop means, resilient means 'to retain one of said legs in substantially horizontal position against said stop means with the other leg in upright substantially vertical position, said pawl having a locking finger adjacent said drive finger adapted to engage said horizontal leg to retain the latter against said stop means at the end of the stroke of said plunger, whereby the projection driven by said drive finger will be locked between said drive finger and said vertical leg properly to index said drum.

14. The combination set forth in claim 9 in which said drum assembly has a plurality of plates extending transversely thereacross and equidistantly spaced therearound, means mounting said plates for oscillating movement transversely of said drum, said article holders are mounted on said plates and means associated with each of said plates to effect Vibration thereof.

15. The combination set forth in claim 14 in which the means to vibrate each of said plates comprises an associated air driven vibrator, said shaft has a longitudinal bore at one end and a transverse recess in communication with said bore, a manifold having an opening through which the end of the shaft extends, said manifold having a plurality of spaced bores connected at one end to an associated vibrator and leading at their other ends into said opening, said manifold bores being successively moved into alignment with said recess upon rotation of said drum, whereby when a source of gas under pressure is connected to said longitudinal bore, the vibrator associated with the plate carrying the article holders when at coating station will be energized.

16. The combination set forth in claim 9 in which each of said holders comprises a sleeve extending radially with respect to the drum, 2. collet in one end of said sleeve, a push rod in said sleeve afiixed at one end to the inner end of the collet and extending outwardly beyond the other end of the sleeve, resilient means reacting against said push rod normally to retain said collet in closed position, and means actuated after said holder has been moved from the brushing station and before it has been moved to the coating station, reacting against the outer end of said push rodto move the latter into the sleeve to eifect opening of said collet to receive the article.

17. The combination set forth in claim 16 in which said last mentioned means comprises a cam secured to said shaft, said drum and the sleeve thereon being rotatable about said shaft, said cam having a projecting portion operatively engaging the outer end of said push rod only when the sleeve has been moved from the brushing stationand before it has been moved to the coating station, whereby when said drum is further rotated past said insertion station said collet will be moved to locked POS1iI10H 'by the resiliently urged push rod.

18. The combination set forth in claim 9 in which the article holders are arranged in a plurality of rows each row having a plurality of holders and the plurality of rows of holders extend parallel to the shaft and are equidistantly spaced around the periphery of the drum, each of said holders being rotatably mounted and having a gear secured thereto, idler gears mounted on said drum and engaging adjacent holder gears in each row, one of said idler gears being a drive gear, and means normally spaced from said drive gear and adapted to engage the latter at the brushing station after each rotation of said drum, to rotate said article holders.

19. The combination set forth in claim 18 in which the last named means comprises a vertically movable support, means to reciprocate said supporha motor on said support, brushes on said support driven'by said motor, a gear on said support driven by said motor, said gear being adapted to be vertically aligned with the drive gear in each row and the brush means being adapted to be aligned with the articles in the holders in each row after the drum has been rotated to each station, whereby when the reciprocating means has moved the sup port downwardly, the motor driven gear will engage the drive gear to rotate the holders and the brushes will engage the articles.

References Cited in the file of this patent UNITED STATES PATENTS 1,563,714 Blue Dec. 1, 1925 2,119,914 Holzcher June 7, 1938 2,239,414 Eddison Apr. 22, 1941 2,325,126 Giesler July 27, 1943 2,377,632 Keller June 5, 1945 2,424,261 Toulmin July 22, 1947 2,431,781 Wagner Dec. 2, 1947 2,483,424 *Martines Oct. 4, 1949 2,607,317 Sidnell et al. Aug. 19, 1952 2,664,874 Graham Jan. 5, 1954 2,683,436 Marantz July 13, 1954 2,706,693 Heller Apr. 19, 1955 2,706,694 Haller Apr. 19, 1955 2,752,268 Whitfield et a1. June 26, 1956 2,755,205 Robb et al July 17, 1956 2,763,921 Turner et a1 Sept. 25, 1956 2,774,686 Hodge Dec. 18, 1956 2,781,738 Paasche Feb. 19, 1957 

